I'm sorry, just bought a Windows 8 Pro tablet this Xmas and I'm very unimpressed with Microsofts App Store. It just seems like it has an unorganised list of application with no overall ideo of best sellers or even per category. They need to take a leaf out of Apples book, it might not be the best way to find new apps, but it helps the best apps rise to the top of the pile.
Apples actual app store (especially when accessing it through iTunes) in my opinion sucks major donkey nuts. Sure there are tons of apps but the usability is just terrible.
I had to help my son use iTunes for his new iPod (our houses only Apple device) after Christmas and I was amazed at just how lousy the usability of iTunes is. Buying apps and getting them on his iPod was just about the most idiotic process I have ever seen.
We have been using Zune software for my families 3 Zune devices since my son was 8 (he is now 14) and everyone has loved just how easy and straightforward it was to use. iTunes has managed to make my son so frustrated that he wants me to come get his iPod set up for him.